Well-designed Z-scheme photocatalyst of NH₂-MIL-125(Ti) MOF coupled g-C₃N₄ with RGO mediator synthesized with a facile hydrothermal method has been investigated for stimulating photocatalytic CO₂ reduction under visible light. The amino-functionalized Ti-based MOF boosted the photocatalytic efficiency due to its high surface area and porous structure. Moreover, the NH₂-MIL-125(Ti) MOF has a great ability for CO₂ gas adsorption. The novel RGO-linked g-C₃N₄/NH₂-MIL-125(Ti) nanocomposite exhibited efficient photocatalytic CO₂ conversion to CH₄ and CO. The experimental results showed that CO was the predominant reaction product with a production of 383.79 μmol g^-1 achieved after 4 h irradiation which is 5 and 2.5 times higher compared to pure g-C₃N₄ and zero-MOF g-C₃N₄-RGO composite, respectively. However, the composite also exhibited a CH₄ evolution of 13.8 μmol g^-1. The amino functionality provided the MOF with antenna-like reaction sites with high affinity to CO₂ molecules which improved the photocatalytic reduction of CO₂ towards high CO production selectivity. An effective spatial separation and transfer of photogenerated charge carriers was also obtained as a result of RGO incorporation which constructed an effective Z-scheme bridge for the transfer of charges and limiting the high recombination rate of g-C₃N₄. The stability analysis of the newly developed composite revealed a continuous production of CO and CH₄ in multiple cycles without any obvious deactivation under visible light. This work provides a new approach for the construction of Z-scheme heterojunction composites that would be beneficial for further investigations in selective CO₂ conversion to solar fuels.

研究了精心设计的NH ₂ -MIL-125（Ti）MOF的g-C ₃ N ₄偶联Z-光催化剂，并用简便的水热法合成了RGO介体，以促进可见光下的光催化CO ₂还原。氨基官能化的Ti基MOF由于其高表面积和多孔结构而提高了光催化效率。此外，NH ₂ -MIL-125（Ti）MOF具有很强的CO ₂气体吸附能力。新型的RGO连接的gC ₃ N ₄ / NH ₂ -MIL-125（Ti）纳米复合材料表现出有效的光催化CO ₂转化为CH _4的能力实验结果表明，CO是主要的反应产物，辐照4 h后产生的产量为383.79μmolg ^-1 ，是纯gC ₃ N ₄和零-MOF gC ₃ N _4的5和2.5倍-RGO复合材料。然而，该复合物还表现出13.8μmolg ^-1的CH ₄析出。氨基官能团使MOF具有与CO ₂分子高度亲合的天线状反应位点，从而改善了CO ₂的光催化还原向高CO生产选择性的方向发展。通过掺入RGO，还获得了光生电荷载流子的有效空间分离和转移，该结构为电荷转移和限制gC ₃ N ₄的高重组率构建了有效的Z-方案桥。对新开发的复合材料的稳定性分析表明，在可见光下，在多个循环中连续生产CO和CH ₄，而没有任何明显的失活。这项工作为Z型异质结复合材料的构造提供了一种新方法，这将有助于进一步研究选择性CO ₂转化为太阳能的研究。